Field of the Invention
The present invention relates to a glass tube cutting device for cutting an end portion of a glass tube having a predetermined length and a glass tube cutting method.
Description of Related Art
For instance, glass tubes used for luminescent lamps, medicinal containers such as ampoules and vials, back light for liquid crystal panels are generally produced by the processes mentioned below.
As shown in FIG. 7, a rough cutting process to obtain a plurality of glass tubes G1 is carried out by cutting a continuous glass tube G0 formed by pulling the tube using, for example, a Danner method for each predetermined length by a rough cutting device 200 while pulling with a tube puller 100. Subsequently, respective glass tubes G1 are fed in a parallel state by a conveyor 300. And a re-cutting process to re-cut both ends of respective glass tubes G1 is re-cut by a re-cutting device 400 to produce f finished goods of glass tubes G1. Subsequently, the glass tubes G1 are conveyed to a delivery process by a conveyor 500.
Conventionally, a cutting device applied to a glass tube ends forming device described in Japanese Unexamined Patent Application Publication No. 54-43005 A is known as a re-cutting device 400 to re-cut ends of a glass tube.
As shown in FIG. 8, the cutting device comprises: a conveyor 410 configured to convey a plurality of glass tubes G1 each having a predetermined length in a direction orthogonal to a tube axis of the glass tube while the cutting device rotates the plurality of glass tubes about tube axes of the glass tubes; a pair of preheat burners 420 provided on both sides of a conveyance route of the conveyor 410, the pair of preheat burners 420 being configured to preheat both ends of portions of the respective glass tubes G1 to be cut; a pair of cutting blades 430 provided on a more downstream side of the respective conveying glass tubes G1 than respective preheat burners 420, the pair of cutting blades 430 being configured to re-cut both ends of the respective glass tubes G1; and a pair of glazing burners 440 provided on a more downstream side of the respective conveying glass tubes G1 than respective cutting blades 430, the pair of glazing burners 440 being configured to glaze an end portion of the respective re-cut glass tubes G1. The cutting device is configured to impose thermal shock and scratches on almost all circumferences of the outer circumference surface of the respective glass tubes G1 by contacting the cutting blades 430 with the outer circumference surface of both ends of the respective glass tubes G1 rotating about the tube axes of the glass tubes. The thermal shock creates cracks resulting from the scratches on the outer circumference of the respective glass tubes G1 and re-cuts the ends of the respective glass tubes G1 at a right angle relative to the tube axes of the glass tubes.